Starch factories generate large amounts of cassava solid waste. A small amount is utilized for animal feed but most of it is discharged with deleterious effects to the envirounment. A edible food with a high content of insoluble dietary fiber (60.9%), named "partially hidrolyzed cassava waste" (PHCW), was prepared from industrial cassava solid waste by an enzymatic process. PHCW or wheat bran (WB) were fed to model rats and both promoted digestive function effects, but PHCW produced the greatest effect. The insoluble fiber constituent from PHCW (and not the soluble fiber), promoted the greatest fecal bulking, fecal weight and defecation frequency in rats, as compared to WB. Such results indicate that the partially hydrolyzed cassava waste presents digestive function properties which allow it to be used as an adequate source of insoluble dietary fiber in the formulation of functional food for human nutrition.